Aligning method, exposure method, exposure apparatus, and device manufacturing method

ABSTRACT

According to an aligning method, positions of measurement marks at a plurality of shot positions on a substrate are measured, measurement values are statistically processed, and a master and the substrate are aligned. When a plurality of measurement marks exist in a shot, measurement marks to be used for alignment are selected from them independently of each other. An alignment measurement sample shot which is not adversely affected by a shot size is selected, so an alignment precision is improved.

FIELD OF THE INVENTION

[0001] The present invention relates to an aligning method, exposuremethod, and exposure apparatus used for manufacturing various types ofdevices, e.g., a semiconductor element such as an IC or LSI, a displayelement such as a liquid crystal panel, a detection element such as amagnetic head, and an image sensing element such as a CCD, and a devicemanufacturing method.

BACKGROUND OF THE INVENTION

[0002] For example, in a photolithography process for manufacturing asemiconductor element and the like, an exposure apparatus fortransferring a pattern on a master (mask or reticle) onto a substrate(wafer or glass plate) coated with a photoresist is used. Recently, areduction projection exposure apparatus which is advantageous in termsof resolution and aligning precision has been used. Usually, asemiconductor element is manufactured by forming multilevel circuitpatterns on a plurality of shot regions arrayed on a substrate by usingdifferent masters.

[0003] A shot array comprised of a plurality of shots arranged on thesubstrate will be called a shot layout. The shot layout is formed byconsidering the size of the substrate, the sizes of the shot regions,the sizes of the chip regions, and the like. A necessary number of shotsselected from the shot layout in order to overlay circuits for formingthe multilevel circuits described above are called sample shots. Thesample shots are usually selected automatically. As a sample shotselecting method, methods disclosed in Japanese Patent Laid-Open Nos.63-232324 and 63-232325 are known. The sample shot selecting method isimportant in overlay accuracy.

[0004] Conventionally, concerning selection of the sample shots, when anarbitrary number of shots are specified, the arbitrary number isarithmetically processed from the shot layout described above on thebasis of the central coordinates of the shots arranged in the shotlayout. As in the conventional case, when the shot size is comparativelysmall and the required precision is comparatively moderate, the shotcenter and an alignment measurement mark position which is used foractual overlaying can be treated to be identical while causing noproblems.

[0005] In recent years, the size of the semiconductor element increases,a region (angle of field) that can be exposed by one shot is widened inorder to improve the productivity, and requirement for improving theoverlay accuracy has become stricter. Thus, an adverse influenceproduced by treating the shot center and the alignment measurement markposition to be identical becomes no longer negligible.

[0006] Conventionally, measurement marks are arranged for eachmeasurement direction (X and Y directions) (X-direction marks arearranged along a transverse scribing line and Y-direction marks arearranged along a vertical scribing line), so a measurement error isminimized. However, in order to improve the productivity, marks withwhich the measurement time can be shortened, i.e., measurement markswith which both the X and Y directions can be measured simultaneously,are employed. Also, in order to correct the shot shape, multi-pointmeasurement marks are arranged within the shot. This makes it difficultto improve the precision when sample shot selection is performed in theconventional manner by treating the shot center and the measurement markposition to be identical.

[0007] As described above, in conventional sample shot selection forperforming overlaying, the arithmetic process is performed on the basisof the shot center. On the shot layout, even if the sample shots can bearranged in the vicinities of positions at the equal distance from thesubstrate center, when the positions of actual alignment measurementmarks arranged in the shot do not correspond to the shot center, themeasurement mark positions are deviated from the substrate center.

[0008] In fact, the overlaying measurement marks in the shot are rarelyarranged at the shot center, and are usually formed in scribing lineregions arranged between shots. Even if the centers of selected sampleshots can be arranged at the equal distance from the substrate center,for example, the X/Y-direction simultaneous measurement mark positionsare displaced from the shot center by half the shot size at minimum.This appears as a deviation amount from the substrate center.

[0009] In an ideal state, this deviation amount does not adverselyaffect the overlay accuracy. In fact, however, a measurement errorcaused depending on the coating uniformity of the resist, and a positiondetection error such as expansion/contraction of the substrate which iscaused by annealing of the substrate exist. When these errors exist andthe deviation of measurement mark positions from the substrate center ispresent, an error occurs in a correction amount obtained by astatistical process, to adversely affect the overlay accuracy.

[0010] For example, assume that X/Y-direction simultaneous measurementmarks are used. When the shot size is 20 mm and a substratemagnification component produced by manufacturing process factors is 5ppm, a shift component produced by the overlaying measurement value isabout 50 nm when compared to a case with no substrate magnificationcomponent. This cannot be neglected when compared to a recent requiredoverlay accuracy of 30 nm.

[0011] It is known that the measurement error caused depending on thecoating uniformity of the resist, and expansion/contraction of thesubstrate which is caused by annealing of the substrate occur radiallyfrom the substrate center and equally concentrically due to themanufacturing process. Also, the expansion/contraction in the radialdirection varies in accordance with the manufacturing process and thedensity of the circuit pattern.

[0012] In order to decrease an influence to the overlay accuracy causedby the manufacturing process factors, the present invention has as itsobject to provide an automatic selecting method for alignmentmeasurement sample shots which is not adversely affected by the shotsize.

SUMMARY OF THE INVENTION

[0013] The present invention has been proposed to solve the conventionalproblems, and has as its object to provide an aligning method, anexposure apparatus employing the alignment method, and a devicemanufacturing method employing the exposure apparatus.

[0014] In order to achieve the above object, an aligning method, anexposure apparatus employing the alignment method, and a devicemanufacturing method employing the exposure apparatus according to thepresent invention are characterized mainly by the following steps andarrangements.

[0015] More specifically, in an aligning method according to the presentinvention, an aligning method of measuring positions of measurementmarks at a plurality of shot positions on a substrate, statisticallyprocessing measurement values, and aligning a master and the substrate,wherein when a plurality of measurement marks exist related a shot,measurement marks to be used for alignment are selected therefromindependently of each other.

[0016] In an aligning method according to the present invention, analigning method of measuring positions of measurement marks at aplurality of shot positions on a substrate, statistically processingmeasurement values, and aligning a master and the substrate, wherein anecessary number of shots to be used for alignment are selected from aplurality of shots on the substrate on the basis of the shot positionsor the positions of the measurement marks.

[0017] In an aligning method according to the present invention, analigning method of measuring positions of measurement marks at aplurality of shot positions on a substrate, statistically processingmeasurement values, and aligning a master and the substrate, wherein anecessary number of shots to be used for alignment are selected from aplurality of shots on the substrate on the basis of distances between acenter of the substrate and the positions of the measurement marks.

[0018] In an aligning method according to the present invention, analigning method of measuring positions of measurement marks at aplurality of shot positions on a substrate, statistically processingmeasurement values, and aligning a master and the substrate, wherein anecessary number of shots to be used for alignment are selected from aplurality of shots on the substrate so as to be distributed in thevicinities of positions with which distances between a center of thesubstrate and the positions of the measurement marks are equal.

[0019] Preferably, in any one of the above aligning methods, when thenecessary number of shots to be used for alignment are selected from theplurality of shots on the substrate, distances between a center of thesubstrate and the measurement marks are calculated, allowable values ofdifferences in distance between the center of the substrate and themeasurement marks are input for all the marks or for each mark, andwhether the allowable values are satisfied is checked.

[0020] An exposure apparatus according to the present inventioncomprises an alignment unit for measuring positions of measurement marksat a plurality of shot positions on a substrate, statisticallyprocessing measurement values, and aligning a master and the substrate;and a projection exposure unit for projecting and exposing a pattern ofthe master onto the substrate aligned by the alignment unit, whereinwhen a plurality of measurement marks exist in a shot, the alignmentunit selects measurement marks to be used for alignment therefromindependently of each other.

[0021] An exposure apparatus according to the present inventioncomprises: an alignment unit for measuring positions of measurementmarks at a plurality of shot positions on a substrate, statisticallyprocessing measurement values, and aligning a master and the substrate;and a projection exposure unit for projecting and exposing a pattern ofthe master onto the substrate aligned by the alignment unit, wherein thealignment unit selects a necessary number of shots to be used foralignment from a plurality of shots on the wafer on the basis of theshot positions or the positions of the measurement marks.

[0022] An exposure apparatus according to the present inventioncomprises: an alignment unit for measuring positions of measurementmarks at a plurality of shot positions on a substrate, statisticallyprocessing measurement values, and aligning a master and the substrate;and a projection exposure unit for projecting and exposing a pattern ofthe master onto the substrate aligned by the alignment unit, wherein thealignment unit selects a necessary number of shots to be used foralignment from a plurality of shots on the wafer on the basis ofdistances between a center of the substrate and the positions of themeasurement marks.

[0023] An exposure apparatus according to the present inventioncomprises: an alignment unit for measuring positions of measurementmarks at a plurality of shot positions on a substrate, statisticallyprocessing measurement values, and aligning a master and the substrate;and a projection exposure unit for projecting and exposing a pattern ofthe master onto the substrate aligned by the alignment unit, wherein thealignment unit selects a necessary number of shots to be used foralignment from a plurality of shots on the wafer so as to be distributedin the vicinities of positions with which distances between a center ofthe substrate and the positions of the measurement marks are equal.

[0024] An exposure method according to the present invention comprises:the aligning step of measuring positions of measurement marks at aplurality of shot positions on a substrate, statistically processingmeasurement values, and aligning a master and the substrate; and theprojecting and exposing step of projecting and exposing a pattern of themaster onto the substrate aligned in the aligning step, wherein when aplurality of measurement marks exist in a shot, measurement marks to beused for alignment are selected therefrom independently of each other inthe aligning step.

[0025] An exposure method according to the present invention comprises:the aligning step of measuring positions of measurement marks at aplurality of shot positions on a substrate, statistically processingmeasurement values, and aligning a master and the substrate; and theprojecting and exposing step of projecting and exposing a pattern of themaster onto the substrate aligned in the aligning step, wherein in thealigning step, a necessary number of shots to be used for alignment areselected from a plurality of shots on the substrate on the basis of theshot positions or the positions of the measurement marks.

[0026] An exposure method according to the present invention comprises:the aligning step of measuring positions of measurement marks at aplurality of shot positions on a substrate, statistically processingmeasurement values, and aligning a master and the substrate; and theprojecting and exposing step of projecting and exposing a pattern of themaster onto the substrate aligned in the aligning step, wherein in thealigning step, a necessary number of shots to be used for alignment areselected from a plurality of shots on the substrate on the basis ofdistances between a center of the substrate and the positions of themeasurement marks.

[0027] An exposure method according to the present invention comprises:the measuring step of measurement marks at a plurality of shot positionson a substrate, statistically processing measurement values, andaligning a master and the substrate; and the projecting and exposingstep of projecting and exposing a pattern of the master onto thesubstrate aligned in the aligning step, wherein in the aligning step, anecessary number of shots to be used for alignment are selected from aplurality of shots on the substrate so as to be distributed in thevicinities of positions with which distances between a center of thesubstrate and the positions of the measurement marks are equal.

[0028] A device manufacturing method according to the present inventioncomprises the steps of: installing a plurality of semiconductormanufacturing apparatuses including an exposure apparatus at a factory;and manufacturing a semiconductor device by using the plurality ofsemiconductor manufacturing apparatuses, the exposure apparatuscomprising an alignment unit for measuring positions of measurementmarks at a plurality of shot positions on a substrate, statisticallyprocessing measurement values, and aligning a master and the substrate,and a projection exposure unit for projecting and exposing a pattern ofthe master onto the substrate aligned by the alignment unit, whereinwhen a plurality of measurement marks exist in a shot, the alignmentunit selects measurement marks to be used for alignment therefromindependently of each other.

[0029] A device manufacturing method according to the present inventioncomprises the steps of: installing a plurality of semiconductormanufacturing apparatuses including an exposure apparatus at a factory;and manufacturing a semiconductor device by using the plurality ofsemiconductor manufacturing apparatuses, the exposure apparatuscomprising an alignment unit for measuring positions of measurementmarks at a plurality of shot positions on a substrate, statisticallyprocessing measurement values, and aligning a master and the substrate,and a projection exposure unit for projecting and exposing a pattern ofthe master onto the substrate aligned by the alignment unit, wherein thealignment unit selects a necessary number of shots to be used foralignment from a plurality of shots on the wafer on the basis of theshot positions or the positions of the measurement marks.

[0030] A device manufacturing method according to the present inventioncomprises the steps of: installing a plurality of semiconductormanufacturing apparatuses including an exposure apparatus at a factory;and manufacturing a semiconductor device by using the plurality ofsemiconductor manufacturing apparatuses, the exposure apparatuscomprising an alignment unit for measuring positions of measurementmarks at a plurality of shot positions on a substrate, statisticallyprocessing measurement values, and aligning a master and the substrate,and a projection exposure unit for projecting and exposing a pattern ofthe master onto the substrate aligned by the alignment unit, wherein thealignment unit selects a necessary number of shots to be used foralignment from a plurality of shots on the wafer on the basis ofdistances between a center of the substrate and the positions of themeasurement marks.

[0031] A device manufacturing method according to the present inventioncomprises the steps of: installing a plurality of semiconductormanufacturing apparatuses including an exposure apparatus at a factory;and manufacturing a semiconductor device by using the plurality ofsemiconductor manufacturing apparatuses, the exposure apparatuscomprising an alignment unit for measuring positions of measurementmarks at a plurality of shot positions on a substrate, statisticallyprocessing measurement values, and aligning a master and the substrate,and a projection exposure unit for projecting and exposing a pattern ofthe master onto the substrate aligned by the alignment unit, wherein thealignment unit selects a necessary number of shots to be used foralignment from a plurality of shots on the wafer so as to be distributedin the vicinities of positions with which distances between a center ofthe substrate and the positions of the measurement marks are equal.

[0032] Other features and advantages of the present invention will beapparent from the following description taken in conjunction with theaccompanying drawings, in which like reference characters designate thesame or similar parts throughout the figures thereof.

BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The accompanying drawings, which are incorporated in andconstitute a part of the specification, illustrate embodiments of theinvention and, together with the description, serve to explain theprinciples of the invention.

[0034]FIG. 1 is a view showing an alignment unit according to anembodiment of the present invention;

[0035]FIG. 2 is a view showing a layout within a shot of measurementmarks (X- and Y-direction independent measurement marks);

[0036]FIG. 3 is a view showing a layout within a shot of measurementmarks (X/Y-direction simultaneous measurement marks);

[0037]FIG. 4 is a view showing a layout of sample shots for overlayingwhen the X- and Y-direction independent measurement marks according tothe present invention are used;

[0038]FIG. 5 is a view showing a layout of sample shots for overlayingwhen the X/Y-direction simultaneous measurement marks according to thepresent invention are used;

[0039]FIG. 6 is a flow chart for determining sample shot selection;

[0040]FIG. 7 is a flow chart showing a semiconductor devicemanufacturing process;

[0041]FIG. 8 is a detailed flow chart of the wafer process of FIG. 7;

[0042]FIG. 9 shows a layout of sample shots for overlaying whenconventional X- and Y-direction independent measurement marks are used;

[0043]FIG. 10 shows a layout of sample shots for overlaying whenconventional X/Y-direction simultaneous measurement marks are used; and

[0044]FIG. 11 is a view showing the schematic arrangement of an exposureapparatus incorporating an alignment unit according to a preferredembodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0045] Preferred embodiments of the present invention will now bedescribed in detail in accordance with the accompanying drawings.

[0046] <First Embodiment>

[0047]FIG. 1 shows an alignment unit according to the present invention.Referring to FIG. 1, reference symbol R denotes a retile; and W, awafer. Reference numeral 1 denotes a projection lens, and referencesymbol S denotes an alignment optical system. Of the constituentelements of the alignment optical system S, reference numeral 2 denotesan alignment illumination unit; 3, a beam splitter; 4, an alignmentscope; and 5, an image sensing device.

[0048] Illumination light from the alignment illumination unit 2irradiates a mark on the wafer W through the beam splitter 3 andprojection lens 1. The image of the mark is formed on the image sensingdevice 5 through the projection lens 1, beam splitter 3, and alignmentscope 4. An A/D converter 6 converts an image sensing signal from theimage sensing device 5 into a digital signal. The digital signal isaccumulated by an accumulator 7 and subjected to position detection by aposition detector 8. Position measurement information of the respectivemarks are statistically processed by a controller 9 and converted intogrid information indicating the position, magnification, and rotation ofthe wafer W as a whole. A stage driver 10 drives an X-Y stage 11 on thebasis of this information to move the wafer W. Reference numeral 12denotes a storage for storing information necessary for the process. Aso-called TTL type alignment unit which detects a mark on the wafer Wthrough the projection lens 1 has been described. Alternatively, anoff-axis alignment unit may be used instead.

[0049] As examples of the layout in the shot according to the presentinvention, FIG. 2 shows a layout within a shot of X- and Y-directionindependent measurement marks, and FIG. 3 shows a layout within a shotof X/Y-direction simultaneous measurement marks. Reference numeral 13denotes an X-direction measurement mark; 14, a Y-direction measurementmark; and 15, an X/Y-direction simultaneous measurement mark.

[0050]FIG. 9 is a view showing a layout of sample shots for overlayingwhen conventional X- and Y-direction independent measurement marks areused, and FIG. 4 is a view showing a layout of sample shots foroverlaying when the X- and Y-direction independent measurement marksaccording to the present invention are used.

[0051]FIG. 10 is a view showing a layout of sample shots for overlayingwhen conventional X/Y-direction simultaneous measurement marks are used,and FIG. 5 is a view showing a layout of sample shots for overlayingwhen the X/Y-direction simultaneous measurement marks according to thepresent invention are used.

[0052] Referring to FIGS. 9 and 10, reference numerals D1 to D4 denoteconventional positions of sample shots. In FIGS. 9 and 10, deviationamounts of a measurement mark from the wafer center are indicated by Oxand Oy. In FIG. 4, reference numerals A1 to A4 denote sample shots forX-direction measurement; and B1 to B4, sample shots for Y-directionmeasurement. In FIG. 5, reference numerals C1 to C4 denote sample shotsfor X/Y-direction simultaneous measurement.

[0053] The present invention is constituted by the first stage ofcalculating, when selecting a sample shot, measurement mark positioncoordinates on the wafer from shot position coordinates and measurementmark position coordinates within a shot, the second stage of selecting asample shot on the basis of the information on the measurement markposition coordinates on the wafer, and the third stage of checkingwhether or not the mark position coordinates of the selected shot arewithin checking information input in advance. These stages will now bedescribed individually.

[0054] Regarding calculation of the measurement mark position of thefirst stage, for example, when the measurement marks arranged in theshot are X- and Y-direction independent marks, the position coordinatesof a sample shot candidate or of the measurement marks of all the shotsare calculated from the mark layout within the shot shown in FIG. 2 andthe shot layout within a wafer shown in FIG. 4. The measurement marksare calculated from the shot position coordinates and the measurementmark position coordinates within the shot. When the mark coordinateposition within the wafer is directly obtained in advance, itscoordinates may be used.

[0055] In the second stage, of the measurement mark coordinate positionspresent within the wafer, those which are in the vicinities of positionsat the equal distance from the wafer center are selected, and that shotwhich has these measurement marks is selected as a sample shot. In thecase of FIG. 4, the X- and Y-direction marks are arranged such thattheir coordinate positions are at the equal distance from the wafercenter. In an actual case, however, the shot layout within the wafer,the size of the shot, and the measurement mark position within the shotvary, and it is impossible to arrange all the measurement marks at theequal distance from the wafer center. For this reason, selectablemeasurement mark coordinate positions are prioritized or conditions suchas a measurement mark layout allowable range are added to them, andsample shot selection is performed, so sample shot selection can beperformed practically.

[0056] The sample shots shown in FIG. 4 are selected completelyindependently in the X- and Y-directions. When compared to a casewherein X- and Y-direction measurement marks related one shot are used,different shots are selected for the respective measurement marks.Consequently, a stage driving distance for alignment measurementincreases, which may decrease the throughput. In view of this, themiddle point between the X and Y mark coordinates may be used as averagecoordinates for selecting the same sample shot in the X and Y directionas the measurement mark coordinates, or as the weighted position of theX and Y coordinates (X and Y barycentric coordinates). Then, sample shotselection more advantageous than conventional one can be performedwithout decreasing the throughput.

[0057] In the third stage, whether the measurement mark positioncoordinates of the sample shot selected in the second step is effectiveis checked. As shown in FIG. 6, first, an allowable deviation amount ofthe measurement mark position is input as Ax and Ay in accordance with anecessary precision (S610). Deviations of the measurement markcoordinates of the sample shot selected in the second stage arecalculated for the respective measurement marks based on the distancesfrom the wafer center which are already calculated in the second stage(S620). These deviations are defined as ΔX and ΔY that satisfy:

ΔX≧Δx  (1)

ΔY≧Δy  (2)

[0058] If the conditions (1) and (2) are not satisfied (S630—No), thisstate is determined as a sample shot abnormality, and the operator isprompted to change the conditions. The operator changes the number ofsample shots and the coordinates of other measurement marks (S640), andperforms sample shot selection again (S650).

[0059] If the allowable deviation amounts can be input for eachmeasurement mark, it is effective in sample shot selection when therequired precision differs between the X and Y directions.

[0060] If the conditions (1) and (2) are satisfied (S630—Yes), theprocess is ended.

[0061] Conventionally, the shot center and the measurement shot positionare treated to be identical (a deviation of the measurement mark fromthe substrate center occurs, as shown in FIGS. 9 and 10). In contrast tothis, as described above, since the measurement marks are arranged inthe vicinities of positions at the equal distance from the wafer center,as shown in FIGS. 4 and 5, no deviation occurs. Therefore, a measurementerror caused by the process, which occurs radially from the wafercenter, does not adversely affect the overlay accuracy, and theprecision is improved.

[0062] Selection of measurement marks at the equal distance from thewafer center has been described. Alternatively, the measurement marksmay be selected in accordance with other conditions.

[0063] <Exposure Apparatus Incorporating Alignment Unit>

[0064]FIG. 11 is a view showing the schematic arrangement of an exposureapparatus incorporating the alignment unit described above. In thisexposure apparatus, a master (reticle, mask) 221 held by a master stage220 is illuminated by an illumination optical system 210. A pattern onthe master 221 is projected onto a substrate (wafer) 241 on a substratestage (wafer stage) 240 through a projection optical system 230, therebyexposing the substrate 241. The alignment unit is adopted in alignmentof the master 221 and substrate 241, and the alignment process isperformed.

[0065] In this manner, with the exposure apparatus incorporating thealignment unit according to the present invention, alignment of themaster and substrate can be performed at high precision, so the exposureperformance of the exposure apparatus can be improved.

[0066] <Device Manufacturing Method Using Exposure Apparatus>

[0067] An embodiment of a device manufacturing method using an exposureapparatus to which the alignment unit as described above is applied willbe described. FIG. 7 shows the manufacturing flow of a semiconductordevice (a semiconductor chip such as an IC or LSI, a liquid crystalpanel, a CCD, a thin film magnetic head, a micromachine, and the like).In step S1 (design circuit), a device pattern is designed. In step S2(fabricate mask), a mask as a mater on which the designed pattern isformed is fabricated. In step S3 (manufacture wafer), a wafer ismanufactured by using a material such as silicon. In step 4 (waferprocess) called a pre-process, an actual circuit is formed on the waferby lithography using the prepared mask and wafer. In step S5 (assembly)called a post-process, a semiconductor chip is formed by using the waferfabricated in step S4, and includes processes such as an assemblyprocess (dicing and bonding) and packaging process (chip encapsulation).In step S6 (inspection), inspections such as the operation confirmationtest and durability test of the semiconductor device manufactured instep 5 are conducted. The semiconductor device is completed throughthese steps, and is shipped (step S7).

[0068]FIG. 8 shows the detailed flow of the above wafer process. In stepS11 (oxidation), the surface of the wafer is oxidized. In step S12(CVD), an insulating film is formed on the wafer surface. In step S13(form electrode), an electrode is formed on the wafer by vapordeposition. In step S14 (implant ion), ions are implanted in the wafer.In step S15 (resist processing), a photosensitive agent is applied tothe wafer. In step S16 (exposure), the above-mentioned exposureapparatus or method exposes the circuit pattern of the mask to thewafer. In step S17 (developing), the exposed wafer is developed. In stepS18 (etching), the resist is etched except for the developed resistimage. In step S19 (remove resist), an unnecessary resist after etchingis removed. These steps are repeated to form multiple circuit patternson the wafer.

[0069] According to this embodiment, in the repeated processes, a highoverlay accuracy can be obtained during exposure (step S16), asdescribed above, so the semiconductor device manufacturing efficiencycan be improved.

[0070] As has been described above, according to the present invention,high-precision overlaying which is not adversely influenced by themanufacturing process can be performed. Since the overlaying operationis not adversely affected by the manufacturing process, the shiftcomponent of the overlaying operation in the process conditionconfirming operation performed at the beginning of a batch process (agroup of substrates that are processed continuously at once under thesame process conditions) becomes stable. Hence, the process conditionconfirming operation can be reduced or eliminated, thereby improving theproductivity.

[0071] As many apparently widely different embodiments of the presentinvention can be made without departing from the spirit and scopethereof, it is to be understood that the invention is not limited to thespecific embodiments thereof except as defined in the claims.

What is claimed is:
 1. An aligning method of measuring positions ofmeasurement marks at a plurality of shot positions on a substrate,statistically processing measurement values, and aligning a master andthe substrate, wherein when a plurality of measurement marks existrelated a shot, measurement marks to be used for alignment are selectedtherefrom independently of each other.
 2. An aligning method ofmeasuring positions of measurement marks at a plurality of shotpositions on a substrate, statistically processing measurement values,and aligning a master and the substrate, wherein a necessary number ofshots to be used for alignment are selected from a plurality of shots onthe substrate on the basis of the shot positions or the positions of themeasurement marks.
 3. An aligning method of measuring positions ofmeasurement marks at a plurality of shot positions on a substrate,statistically processing measurement values, and aligning a master andthe substrate, wherein a necessary number of shots to be used foralignment are selected from a plurality of shots on the substrate on thebasis of distances between a center of the substrate and the positionsof the measurement marks.
 4. An aligning method of measuring positionsof measurement marks at a plurality of shot positions on a substrate,statistically processing measurement values, and aligning a master andthe substrate, wherein a necessary number of shots to be used foralignment are selected from a plurality of shots on the substrate so asto be distributed in the vicinities of positions with which distancesbetween a center of the substrate and the positions of the measurementmarks are equal.
 5. The method according to claim 2, wherein when thenecessary number of shots to be used for alignment are selected from theplurality of shots on the substrate, distances between a center of thesubstrate and the measurement marks are calculated, allowable values ofdifferences in distance between the center of the substrate and themeasurement marks are input for all the marks or for each mark, andwhether the allowable values are satisfied is checked.
 6. The methodaccording to claim 3, wherein when the necessary number of shots to beused for alignment are selected from the plurality of shots on thesubstrate, distances between a center of the substrate and themeasurement marks are calculated, allowable values of differences indistance between the center of the substrate and the measurement marksare input for all the marks or for each mark, and whether the allowablevalues are satisfied is checked.
 7. The method according to claim 4,wherein when the necessary number of shots to be used for alignment areselected from the plurality of shots on the substrate, distances betweenthe center of the substrate and the measurement marks are calculated,allowable values of differences in distance between the center of thesubstrate and the measurement marks are input for all the marks or foreach mark, and whether the allowable values are satisfied is checked. 8.An exposure apparatus comprising: an alignment unit for measuringpositions of measurement marks at a plurality of shot positions on asubstrate, statistically processing measurement values, and aligning amaster and the substrate; and a projection exposure unit for projectingand exposing a pattern of the master onto the substrate aligned by saidalignment unit, wherein when a plurality of measurement marks exist in ashot, said alignment unit selects measurement marks to be used foralignment therefrom independently of each other.
 9. An exposureapparatus comprising: an alignment unit for measuring positions ofmeasurement marks at a plurality of shot positions on a substrate,statistically processing measurement values, and aligning a master andthe substrate; and a projection exposure unit for projecting andexposing a pattern of the master onto the substrate aligned by saidalignment unit, wherein said alignment unit selects a necessary numberof shots to be used for alignment from a plurality of shots on the waferon the basis of the shot positions or the positions of the measurementmarks.
 10. An exposure apparatus comprising: an alignment unit formeasuring positions of measurement marks at a plurality of shotpositions on a substrate, statistically processing measurement values,and aligning a master and the substrate; and a projection exposure unitfor projecting and exposing a pattern of the master onto the substratealigned by said alignment unit, wherein said alignment unit selects anecessary number of shots to be used for alignment from a plurality ofshots on the wafer on the basis of distances between a center of thesubstrate and the positions of the measurement marks.
 11. An exposureapparatus comprising: an alignment unit for measuring positions ofmeasurement marks at a plurality of shot positions on a substrate,statistically processing measurement values, and aligning a master andthe substrate; and a projection exposure unit for projecting andexposing a pattern of the master onto the substrate aligned by saidalignment unit, wherein said alignment unit selects a necessary numberof shots to be used for alignment from a plurality of shots on the waferso as to be distributed in the vicinities of positions with whichdistances between a center of the substrate and the positions of themeasurement marks are equal.
 12. An exposure method comprising: thealigning step of measuring positions of measurement marks at a pluralityof shot positions on a substrate, statistically processing measurementvalues, and aligning a master and the substrate; and the projecting andexposing step of projecting and exposing a pattern of the master ontothe substrate aligned in the aligning step, wherein when a plurality ofmeasurement marks exist in a shot, measurement marks to be used foralignment are selected therefrom independently of each other in thealigning step.
 13. An exposure method comprising: the aligning step ofmeasuring positions of measurement marks at a plurality of shotpositions on a substrate, statistically processing measurement values,and aligning a master and the substrate; and the projecting and exposingstep of projecting and exposing a pattern of the master onto thesubstrate aligned in the aligning step, wherein in the aligning step, anecessary number of shots to be used for alignment are selected from aplurality of shots on the substrate on the basis of the shot positionsor the positions of the measurement marks.
 14. An exposure methodcomprising: the aligning step of measuring positions of measurementmarks at a plurality of shot positions on a substrate, statisticallyprocessing measurement values, and aligning a master and the substrate;and the projecting and exposing step of projecting and exposing apattern of the master onto the substrate aligned in the aligning step,wherein in the aligning step, a necessary number of shots to be used foralignment are selected from a plurality of shots on the substrate on thebasis of distances between a center of the substrate and the positionsof the measurement marks.
 15. An exposure method comprising: themeasuring step of measurement marks at a plurality of shot positions ona substrate, statistically processing measurement values, and aligning amaster and the substrate; and the projecting and exposing step ofprojecting and exposing a pattern of the master onto the substratealigned in the aligning step, wherein in the aligning step, a necessarynumber of shots to be used for alignment are selected from a pluralityof shots on the substrate so as to be distributed in the vicinities ofpositions with which distances between a center of the substrate and thepositions of the measurement marks are equal.
 16. A device manufacturingmethod comprising the steps of: installing a plurality of semiconductormanufacturing apparatuses including an exposure apparatus at a factory;and manufacturing a semiconductor device by using the plurality ofsemiconductor manufacturing apparatuses, the exposure apparatuscomprising an alignment unit for measuring positions of measurementmarks at a plurality of shot positions on a substrate, statisticallyprocessing measurement values, and aligning a master and the substrate,and a projection exposure unit for projecting and exposing a pattern ofthe master onto the substrate aligned by said alignment unit, whereinwhen a plurality of measurement marks exist in a shot, the alignmentunit selects measurement marks to be used for alignment therefromindependently of each other.
 17. A device manufacturing methodcomprising the steps of: installing a plurality of semiconductormanufacturing apparatuses including an exposure apparatus at a factory;and manufacturing a semiconductor device by using the plurality ofsemiconductor manufacturing apparatuses, the exposure apparatuscomprising an alignment unit for measuring positions of measurementmarks at a plurality of shot positions on a substrate, statisticallyprocessing measurement values, and aligning a master and the substrate,and a projection exposure unit for projecting and exposing a pattern ofthe master onto the substrate aligned by said alignment unit, whereinthe alignment unit selects a necessary number of shots to be used foralignment from a plurality of shots on the wafer on the basis of theshot positions or the positions of the measurement marks.
 18. A devicemanufacturing method comprising the steps of: installing a plurality ofsemiconductor manufacturing apparatuses including an exposure apparatusat a factory; and manufacturing a semiconductor device by using theplurality of semiconductor manufacturing apparatuses, the exposureapparatus comprising an alignment unit for measuring positions ofmeasurement marks at a plurality of shot positions on a substrate,statistically processing measurement values, and aligning a master andthe substrate, and a projection exposure unit for projecting andexposing a pattern of the master onto the substrate aligned by saidalignment unit, wherein the alignment unit selects a necessary number ofshots to be used for alignment from a plurality of shots on the wafer onthe basis of distances between a center of the substrate and thepositions of the measurement marks.
 19. A device manufacturing methodcomprising the steps of: installing a plurality of semiconductormanufacturing apparatuses including an exposure apparatus at a factory;and manufacturing a semiconductor device by using the plurality ofsemiconductor manufacturing apparatuses, the exposure apparatuscomprising an alignment unit for measuring positions of measurementmarks at a plurality of shot positions on a substrate, statisticallyprocessing measurement values, and aligning a master and the substrate,and a projection exposure unit for projecting and exposing a pattern ofthe master onto the substrate aligned by said alignment unit, whereinthe alignment unit selects a necessary number of shots to be used foralignment from a plurality of shots on the wafer so as to be distributedin the vicinities of positions with which distances between a center ofthe substrate and the positions of the measurement marks are equal.